Like most on this forum, I open lots of credit cards every year.
And obviously I close most of them within 12 months.
Because most of my spending is for legitimate business expenses, there needs to be a fair amount of recordkeeping in case of an audit.
So I keep the cards in case I need to call the bank issuer and request old statements.

The ziplock bag is getting full, and it's getting more and more confusing.

The obvious solution is to put the information into Quickbooks where the records are kept and get rid of the card...but I kind of feel more comfortable having a physical card.

Does anyone else keep the closed cards or am I crazy?